While acknowledging that we can’t judge books by their covers, how much does the design of a book affect your reading enjoyment? Hardcover vs. softcover? Trade paperback vs. mass market paperback? Font? Illustrations? Etc.?
If I'm in a bookstore, the cover might entice me to pick up the book and at least read the synopsis on the back. Now that I shop for most of my books online, the cover is less likely to be a factor. I generally prefer trade paperbacks, because mass market ones seem to feel "cheap" - flimsy covers, stiff pages that fall out when you open the book too far.